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Jan. 30, 1923.

G. M. LITTLE. ELECTRIC RsslsnNcgz TUBULAR FURNACE.

Fl LED MAR.

VIII/1171111111! INVENTOR QaazMLz'i/Za ATTORNEY WITNESSES:

imam

Patented Jan. 30. 1923.

' UNITED STA1I E-"S PATENT OFFECE.

generics onrrg'rsnonen, rm symzime nssrendn no wnsrmcnousn annotate .2 morscrtrnma comnmzxn com'ommon or rmnqsnvnms.

mBIG-TANCB TUBULAR. FURNACE.

Appueacionmca Karen 38, 1921. Sel'ifl'fl'o. 454.777.

Toall plwmitmay comm: V w-ZBBihknOwnthat I} Gnome M; Lrrrm, a. citizen-of the' United. States, and aresident i of =Pittshurghg inrthewoulity of lAlleghen' 5 andistateiof Pennsyli'aniafihave in a. new andSuseful: Im rovement. iii=Electric- Besistancel'llibuluri rnzicesr-of whichpthe followingiis a'fipcification; 1 Myf'zinventidn ".1 relates: to; :elccu'ial iurn'aces end ame; partidulauly'rtoiiurnsces-aof e ztybe mmplojzedrft'o give meenz rsistanoe rocls an -initiatli baking: Tomonstfuct: ilfurnfice thiitiwill efiieientl'v baikeimstence rodsi-lmsr-alwaysheenligliflie 15 eultiwI't hesib'en ioumlathaflthe be'shwaytd obtei'n predict iszrto suhjeckhll reds 6o 'itll' same; cycle bf rtreetmentsr i :To Wampum 5. tl 1is;:-I have; (levisedea. lfurnace in' which Ythe rods maynenterit one (inch and hebushed through and out at the: otheniend smthdtielllotthe "rods'receive the-same treatinent;

-Sinccfirnaces obtheutypeiindicated are subject tordisintegra'tion; Eit i511 notcontinueus: and :steady (Heat: but also zonevin which all parts are easy-ofhccsso-to: enable Y broken" o'rz-womr parts tozzb'e replioedzfi 'Mywinvention -comprises..a.n-E heater tuhe'fof re'siste'nce' materielthe central bortion'of ivhichlis consiposed of=-ax'plur:ility;of annular selsions. urrounding-,the=hes ter tube is an outerfsliell packed-with afresxstance material capable of retaining heat. such as lampblack.

' Located near the enuso'f the heater tube are thin elastic metallic and plates which are firmly :clampedw-toc thenouter shell; and serve tdcsupport metallic aclnng contg ners aroundthetuhe ends, an to memtain a. suhstantiully'constant pressure on the heat retaining material. The packing containers are filled with some crushed ooncluctwesubstance, such :as graphite; sothat terminals of the current main applied to the end plates electricity to flow to and from the heater tube. The endplates and the outer shell are insulated from each other 1 and-ere held'togthcr by insulated clamps. I p'rovide'elso means carried by the packing containers L'fOl" compress ng the heater tube tolhold the sections in-eligmnent. ohjectofiny invention isle-construct I an electric furnace in which the pextsmay be easily taken Kevin and 'in which any partsubject to-waror disintegration may be quicklyiendieesil'y ne'paired. zAnoth'er object-of my invention is to construct a'simple and durable electric furnace in which the greatest he'atiis at the center of the-furnace 1where the-loss bv radiation or condiictibn' is least.

--::'With'thess' and; other objects IXIY'YIEW, which-maybe incident to the improvements, ray-invention consists in the quarts and combinptions' 'i to. he, herein-nfter set forth and claimed, with the understanding that-the 'necessei'ypleinents cmnprising my ini'entiori may bewniied' .intheir proportions andarrangement without departing from the scope i (if. the i appended claims. .rrlnzhrdew to 1' make my invention inore clearly nnderstoodfl have shown, in the ccompen' fdrawingsj meensfor carrying-the "same intopractical effect without the foi'ements. their useful agglications to e particular constructions. w cliifoi' the pu .of:explanatic'm, have b'een' made: theFsub ect -'o-illustration.

the-.;drawings,- Figure -1' illustrates a lo 'tutlinelisectioii-throu'hmyzfurnace;

illustrates nn-en view'of the fur- Referrmg-totne drawings, a heater tube lris shown composedofgraphite or other suitable resistance material, :a. considerable portion. intermediate its entls .bcing cumlziosed -ofoinnular sections-2 in order to increasecthenelectricel Iresistanceof this portion and thus ensure the production of the highest temperature-therein. The annular sections 2'ere heldin place by pressing the ends of the tube toward the eentergas will be-hereinaftendescribedi The heater tube 1 is mounted within e cylindent; which may he an iron pipe if suitable, insulating members are employed in connection therewith or :asbestosib'oard may be employed: thereby rendering-qother insulating materials unnecessary.-- The cylinder 3 is provided with annula'r fl -5-a.t itsends-end is closed at ea'chmfld; thin elastic'end plates 6. A plurality. of co-operating openings 7 is providediin-eechgofztherflanges fiend the end lates 6'00 permit oflocating therein insuated-holts-8 provided;.with nuts'9 to secure the plates fi egainstithe B82568 5;

To insure thatthere'sh be-no passage broken graphite 1 9j"u of current between the cylinder and the end plates, I provide two non-cowlueting rings 10 between the said. plates eiidi'theemmlur flanges 5. The rings 10 may be formed of ny suitable e em iet ng, -wnd n e en e a revent any passag their im e ename plates 6 and the cylinden of current between end Between heater tube 1 and the outer shell 3. is placed finely onnd lnmpblanln' asiadicated by numer 11, this lampblnck being compressed about the'hentmi tube by means of screws 12: By removing the-screws 12 openings ale pronidedin the cylinder-3 to permit oi introducing-additionnlr quantities .oflampblack, should? this become necessary, by meson ofthe wasting aim? ofvthe original: mass. Screwed into thecenberofi the outer shell 3 is a sight cap. 131 linvixg-a: downwn'rdiyproieebinig sight tnbl fl 7 he cap ermits: the obseiwen v roughly the degree of heat at flae oenter pt :11 furnace by noting-the colon oflthelieaben tn 1.

As, the mmpbmcte may become elactneally conductive 'whnfiheated by the'- action 05 the resistor. andl'ceusei cumentwtof be shunted therefil'oni, e'pluralityofinsulnting v be located at suite lepldces imtheimess lampblaeln' Theyiiaverof suchfinbepnwl andoxternahdimensio as around -the:tnbe 1-' an =inei'de'o'fl 510%: 1 inden 3:

The elastie-end pletesfi: ere mvided1with packing; containers 1! e0 'ng of hqrL zontallyprojecting. annulaz flanges, pref- A bern'iersleqwhichameibemwdeofmabestos,

erebly l formed integrally? :"witln; 'theii end plates." Bhe'paeking. eonmineis 215:, are

adapted to fit around the ends of'the tube 1;. and areprovided with-scazew'threeds 16 upon which are screwedmapeih'f; lieving apex-hires 18 through their centers. "IIh e diameters of the apertures 18' are approximately equal to the 'diemeten ofi the mtenior of the heater tube 1. The packing contain ers '15 uve filled' with broken g-rnphite 1'9; and screws 20 serve to adjust the-pressure of that materinh upon eheaber tube 1;. By adjusting the po eition ofi -th'e senews 2O anv'de'siredi degree of measure of the on e heatertube 1 may he obtained, t erebyinsuring the pmpei; conductionof the eleotnic curcent to and from the heater; tube-without waste Through the caps- 12" PQSSIISCFBWISQI, 2t that bear. a't their inner ends, onwashers 221 that, in turn. been I ;t h eof the heater tube 1. By gi 'itably taghtemngi the scnensfll any desirecl degfe oi eompresiion Illa-y be brou1b tobegr-fipon-thementen of the heater tu e l. wheyeby -the annula r: sections 2-of*tl i at-tube arQ-held3in 4 I "611; The elastieitiy oi the end; plates a'i it! k e in this pressure comm.-

To conduct the current through the tube,

conductors, 23. are suitably atteqhed; to the end: plates. 6.

One of-the caps 17 lowted at the leaving .endoi the furnagqis provided with unextens n 24, of. snitahle length to permit'of the rods coolingtherein and to prevent ogidntion ofithe-eode while pasing therethrongh. By the time the rods have passed the extension 24: they will be cooled sufliciently to be safe from further oxidatlOIL l In use, electricity is conducted from the conductors 23, through the-end plaltesfiand the broken graphite 19in the pa conminers 15-, to the ends ofi th heeter'tnbe 1'. The anmdeu sections.2 of: the heater tube cause the centwt portion of the tube. to have the highest temperature, andthede gree of temperature may be ascertained throughsight'caplB b inspecting the colon of the heater tube. efurnace, once been started, willa'maintein. an even degreeef heat for: aslongtime,:beeause'the leinpblack 1-1 in closely packed.- about .the hasten tube and acts. as an etfioienfi heat insulatoii Green: unhaked rods-ere; slowly pushed thnou h this furnace et'sueh note ofisgeed maths; am thoroughly time by the me they hwve-passed'thedength-oi-th heater-tube.

f-All parts. of my menace: erequmkly; acceseible for repair. The eentral portion of the henten tube-maybe removedfim a; few

minutes b removing the, clam-ping bolts 8, new -enn anseobions 2 p116 invplnoe, and

the furnace lie-again putinFoper-ation in. a short space of'tuney,

While]? heye shown one one-embodiment of m invention, it? is home understood 'thet modi cations may be made therein without departing from the spirit thereof], 'nnd. I desire therefore, that my invention shall: be limited-only as set forth; inbhe appended cleimsfon bythe showing; of: thea'pniornet.

I claim as my invention:

Ana-electric funnece oompnisingmhonter tube ofresistnnee mabenial: duuided into sec: tions, 2' heabstoring means around theitube, compression-means to hold the; sections-togethev, and means for conducting mzelectrioal' current to and item. the beaten tube;

2. Amelectrical furnace o'om ,zisinga heater tube of resistance: materi d'in'aded intoseobions, an-outo'n shell; heat stovingrm ter-iell between the: beaten tube. and 'out'eo shell, end plates: and? means; cosopana' a with the end-plates to-lteepthe beaten-tn (2 under pressure.

3.- An electrical furnace: com msm 1 a heater tube ofi msismncm metering co c.- hive end=plehes-,- a puchhlg eonta-inen-on eeeh end plate, and condncliive pinching inithelpeeking conteinexstmcnndudmeumnt to-andl'fimmitilheaiemtuhm am-5m 4 An sleek-mat iuruam mggprising a hmting means, a packing emlbfl-lmt It amh and of the hunts: mans, and 1e urking matariml in the eontahwri to con duct current to and imam $11: 118111521312.

5. 3m elmricu] tu -mm wggprlsmg a lwuti V mums a plmklltg at again and a the lmt'm Imam, umduntna aekmg material in $114; oontflimvs w 00mm? his 0111 mm to and the heatar means, and means 91* maintaining the mnductiw pack- "mg material under flamma- An electrical rum compmsmg i1- haating mews, a packing main- 1 at 6M1! end of the heat-a1- malms, caps in: he acking cclnflinms, conductive paak ing ma s a! in the containers, and oampresmnn screws to keep the cumltmtim material under pm- 7. An elecarinnl furnace cum a heater tube of resistance mammal: m OHM! shall surrounding the helm! E'Libfl, llamt-aturiug minim], bat-mu Ilka ligltfil tube and the uumr uimll. and plates mgulafzad fm'm the 011m shell means fmkpupmg flu heatslworing material under pmaemm, smci mews hr conducting entrant to and Item the heater tube.

8, Au qflautrieal furnace 00m riaing a heater tube of resistance mutami an flatmshell surrmmtfing the ham: tube, t-stur- -in;; material batman the 110W tube and mamas imc-undncting warrant throw the intq seetiuns, a mat-inn at and 00m uteuqh 12 An elmhfieal fammca a heater tube nf I. minim. 'dm' d inbo awh'una, In oniaryhall $111: hemr tnlba, hmt'itdmg between $21: heater tuba ind the auteur and plum llil 18in mm for mminilining the; MD! J g In mrial under museum and 1101* pwmitgmg the addition of new heat-mung warm and 75 heater tube.

18. An "5;. a 1mm: tpbe at matarm d 'ud into minus, an o uber slmll sm-munding flu: mm tube, lam-an batman the heater tuba Billi cum 311511, and plum inmhbafl the other EMU, cam pmmfiun scrum-s fur mg tlm heatsim'ing am] far pernaming the m d-6mm matmnL pmk' 151g 8 w th; and pI-atag, conductwra fickmfinmmnal m the cape Mr -11: i;geunfialmlnizuna adj ed mfiu n tahaandaoithahealmt and balls rthrcmgh the cups 811d buntimwulmnn ffwm h m .2 Ol lf 'azuLu mm W m L my name filis lath flay cf Much,

GEORGE M. LITTLE. 

